G100(P) Hyperinsulinaemic Hypoglycaemia of Short Duration – Can It Be Associated with Severe Hypoglycaemic Brain Injury?

Abstract

Background Neurological damage is a known risk associated with hyperinsulinaemic hypoglycaemia (HH). Insulin suppresses ketone body
formation and hence no alternative fuels are available for the brain to use; however it is not yet known how long HH has to
last to cause brain injury. We report that neurological damage can occur after a short time in term, normal weight infants
with diazoxide responsive HH.

Aim To describe the clinical course and neurological outcome of 3 term neonates with severe hypoglycaemic brain injury who were
not diagnosed with HH for at least 72 hours.

Methodology 3 patients who presented in the neonatal period with biochemically confirmed HH were recruited. Detailed clinical information
was collected including MRI brain reports.

Results All three term neonates were discharged home after 24–36 hours of birth. Birth weight range was 2730–3460 gms and each delivery
was classified as normal vaginal births with no associated risk factors for HH. All infants presented to the Emergency department
on day 3 to 4 of life with non-specific symptoms like poor feeding and lethargy. However all of them were noted to have jerky
and seizure like movements. Biochemically, all had their true blood glucose levels less than 0.6 mmols/L with raised insulin
and suppressed ketone body formation They all successfully responded to small doses (5mg/kg/day) of Diazoxide (two of them
are off Diazoxide now and had transient hyperinsulinism). Each neonate had MRI brain due to clinical neurological concerns
within the first few weeks of life that showed significant evidence of hypoglycaemic brain injury like gross white matter
changes with parieto-occipital infarcts.

Conclusion It is very important for early identification and prompt management of HH as untreated severe hypoglycaemia can result in
severe brain injury and subsequent neurodevelopmental handicap. Term infants with no risk factors are often difficult to identify
due to non-specific symptoms. Parental education to recognise early symptoms of hypoglycaemia would be recommended and prompt
medical advice should be sought. Blood glucose levels should be of utmost priority for babies presenting to A&E with non specific
symptoms such as poor feeding/lethargy etc.